Flameproofing compositon, method and article containing same



3,3@5,4i3i Patented Feb. 21, 1967 t F 3,305,431 FLAMEPROOFKNG C(JMPOSZTION, METHOD AND ARTICLE CUNTAHNING SAME George J. Peterson, Park Forest, ill., assignor to Swift & Company, Qhicago, 111., a corporation of lillinois No Drawing. Continuation of application Ser. No. 8,516, Feb. 15, 1960. This application July 17, 1963, Ser. No. 295,835

Qlairns. (Cl. 161-432) This invention relates to the treatment of cellulosic materials and more particularly to a method whereby combustible cellulosic materials can be rendered fire and flameproof and also provided with a coating of adhesive material. More particularly, the invention relates to a composition and means for employing said composition in the treatment of cellulosic materials whereby the cellulosic materials can be fiameproofed and bonded either to themselves or to other substrates.

This application is a continuation of application Serial No. 8,516, filed February 15, 1960, and now abandoned. The principal object of the invention is to provide a composition and means whereby cellulosic materials can be coated with a flameproofing adhesive composition so as'to permit bonding of the coated cellulosic material to other cellulosic materials or noncellulosic substrates while imparting to the coated cellulosic material combustion inhibiting or retarding properties.

Another object is the provision of a fiameproofing adhesive composition and laminated webs of cellulosic material which possess an improved resistance to combustion.

Additional objects, if not specifically set forth herein, will be readily apparent to those skilled in the art from the detailed description of the invention which follows. ,The compositions of this invention comprise dispersions of a filmforming adhesive, a halogenated aliphatic compound, and a salt of a metal such as arsenic, antimony, bismuth or tin. The invention contemplates applying this flameproof adhesive mixture to the surface of paper, fabric, wood or other essentially cellulosic fi brous material, spreading said flameproof adhesive over the surface in a continuous film and causing said cellulosic material to be bonded either to other cellulosic materials or to noncellulosic substrates. The invention has particular application in the treatment of paper, specifically heavyweight paper such as is employed in the building trades, although other paper stock, jute, woodpulp, cotton, etc., may be bonded to other material. Veneer board comprising several thin layers of wood cemented together may vary advantageously be manufacturedwith the subject compositions. The material treat ed need only be one which can be bonded with the adhesive element of the composition, yet should .be sufficiently porous so that the halogenated, aliphatic, organic material can impregnate the fibrous material and migrate away from the adhesive bond inasmuch as the halogenated material is incompatible with the adhesive component, particularly after the adhesive bond is formed and dry.

More particularly, the invention includes a method for coating and impregnating fibrous absorbent cellulosic materials, particularly in web form, with a smooth mixture containing a major amount of an adhesive base and lesser amounts of halogenated, aliphatic, organic compositions and water-insoluble salts of antimony, arsenic, bismuth and tin. The composition is applied on the surface of the fibrous material, such as paper or wood, in the form of a continuous film, and the coated cellulosic base is then bonded either to another cellulosic material or to a noncellulosic substrate. Laminated materials represent a favored area of use of these compositions, particularly laminated webs or sheets such as are employed in the preparation of insulation materials in the building trades and also where sheets of wood are bonded together to form a veneer.

The fiameproofing adhesive composition comprises about 10-80% of an adhesive known in the art as a suitable cellulose adhesive, about 10-80% of a halogenated fatty acid derivative such as a halogenated fatty acid ester, halogenated fatty alcohol, amide, ether, etc., and about l080% of a salt of one or more of the metals, antimony, arsenic, bismuth or tin. The fiameproof adhesive mixture is prepared preferably by dispersing the metal salt in a halogenated higher fatty acid derivative and the suspension is agitated vigorously to produce a homogeneous slurry. The smoothness of the suspension or dispersion is increased with increased agitation. If the adhesive is in liquid form at room temperature, it is then added to the slurry with agitation. If the adhesive is not liquid at room temperature, it is heated prior to mixing with the slurry to liquefy the adhesive. Although the adhesive must be incompatible with the halogenated composition in order to insure migration of the halogenated material into the cellulosic base, thorough mixing insures that these components will not separate and a smooth, stable dispersion is formed.

The adhesive component of the mixture, as mentioned previousely, comprises the major portion thereof and can be any known adhesive adapted for use with cellulosic materials such as the animal and vegetable-derived adhesives, glue, rosin, starch, soybean flour, casein adhesives, etc.; also, synthetic adhesive compositions such as emulsions and dispersions of polyvinyl alcohol, polyvinyl acetate, latex, and compounded adhesives are suitable. The adhesive should be insoluble in or immiscible with the halogensupplying element, and this incompatibility must also extend to the composition in the dry form.

The halogenated material can be a mono-, di-, or polyhydric aliphatic alcohol ester of a halogenated fatty acid of 1030 carbons, such as brominated soybean oil, brominated sesame oil, brominated safilower oil, and brominated rape seed, linseed, menhaden, cottonseed oils, lard, tallow, or the fish oils. Generally, halogenated animal, vegetable, and marine triglyceride having more than about 20% halogen can desirably be employed inasmuch as these compositions are, for the most part, low viscosity fluid materials which are readily available. The halogenated component of the mixture can also be a mixture of halogenated materials, such as a mixture of brominated soybean oil and brominated cottonseed oil or other brominated glyceride oils. Also, the halogen-substituted higher fatty acid esters of aliphatic glycols and aliphatic tetritols, pentitols, and hexitols may be used. While derivatives of chlorinated fatty acids may be employed, it has been found preferable to employ the brominated derivatives inasmuch as it appears that less of the brominated derivative is required to obtain a given amount of fiameproo-fing. Usually the flameproofing composition contains at least about 15% of the halogenated fatty acid derivative. However, in some cases, the fiameproofing composition may contain only 10%halogenated fatty acid derivatives if other halogenated compositions are present.

The metal salt which is part of the composition and which may include oxides and sulfides of arsenic, antimony, bismuth, and tin, should be present in an amount of at least based on the weight of the adhesive mix. The salt should be water-insoluble and includes such salts as antimony potassium tartrate, antimony oxide, antimony trisulfide, bismuth trisulfide, and the sulfides of tin and arsenic. Also, the double salts of these metals such as lead antimonates and the arsenates may be employed. In preparing the adhesive mix the metal salt is dispersed in the halogenated material, and the dispersion is vigorously agitated with the adhesive to obtain a smooth, homogeneous mixture.

The material treated may be any fibrous, absorbent, cellulosic material which will absorb the halogenated composition. Cellulosic materials such as paper, wood, structural board (wallboard), cotton fabric, etc., may advantageously be adhered to webs of the same type of material or to other non-cellulosic substrates such as metal, plastics, and noncellulosic fibers. The fiameproof adhesive material is particularly useful in the lamination of paper, specifically heavyweight paper, to webs of the same material or to metal foil or to wood. Paper, such as unbleached kraft paper (37 lbs. per ream), is employed in the preparation of insulating sheet, and it is often necessary to bond sheets of this heavyweight paper to metal foil, specifically alumium foil. The flameproof adhesive in this case is deposited on the surface of the foil or the paper in a thin, substantially continuous layer, and the webs of paper and foil are pressed together. Also, laminates of wood are formed in the same fashion to provide fiameproofed veneer. It can be appreciated that larger amounts of the flameproofing adhesive will impart greater combustion resistance to the material being treated although it can be stated generally that if the fiameproof adhesive contains at least of the halogenated fatty material and the fatty material contains about 33% or more halogen, a laminate having very desirable fire-retardant properties will be provided.

The amount of fiameproof adhesive to be employed in providing satisfactory combustion resistance is expressed as the amount of halogenated fatty material based on the weight of ceilulosic material being treated. Usually about 13-50% brominated glyceride such as brominated cottonseed oil or brominated soybean oil based on the weight of paper or other porous cellulosic material provides good flameproofing. Larger amounts of the halogenated composition are required if chlorinated rather than brominated glycerides are used. In a preferred embodiment, 1335% of the brominated oil based on the weight of cellulosic material is employed. While larger amounts impart good flame resistance to the paper or like material, the use of larger amounts is not recommended since the degree of increased flameproofness is not commensurate with the added cost.

A preferred fiameproof adhesive containing:

Percent by weight Brominated soybean oil (30% bromine) Everflex-B polyvinyl acetate emulsion 1 (55% solids)- 65 Antimony oxide 15 See footnote 1 below.

1 Vinyl acetate-maleic 'anhydride copolymer-Everfiex-B described in Bulletin E-13, March 1955, of the Dewey and Aliny Chemical (10., Cambridge, Mass.

Example I The following ingredients were admixed to form a smooth dispersion:

Parts by weight Brominated soybean oil (35% bromine) c 22.5

Everfiex-B polyvinyl acetate emulsion 1 (55% solids) 66.5

Antimony oxide 11.0

The following formula was prepared substantially in accordance with the method set forth in Example -1 above:

Parts by weight Water 42.5 extrin c- 18.0 Borax 2.0 Sodium metasilicate 2.5 Antimony oxide 15:0 Brominated soybean oil (35% bromine) 20.0

When this material was deposited on the surface of 30. lb. kraft paper, this paper laminated with another untreated web of 30 lb. kraft paper, and the laminated material dried, the laminate showed excellent resistance to the development of combustion when subjected to the standard ASTM flameproofing test.

Example 111 A hot melt adhesive was prepared by dispersing antimony oxide in brominated soybean oil and this dispersion was admixed with melted microcrystalline wax and W. wood rosin and also ethyl cellulose. The formula of the hot melt, flameproof adhesive is as follows:

. Parts by weight W. wood rosin 46 Microcrystalline wax (M.P. 195 F.) l0 Ethyl cellulose 9 Antimony oxide 15 Brominated soybean oil (35% bromine) 20 The following composition:

I I Parts by weight Casein solution 38.75

Modified rosin emulsion (65% solids) 15.0 Neoprene latex (50% solids) 33.0 Antioxidant Q 0.75 Zinc oxide 0.5 Antimony oxide 11.0 Brominated soybean oil (3 5 bromine) 1 1.0

was tested for flameproofing properties in a laminate of 30 lb. kraft paper bonded to another sheet of 30 lb. kraft. The laminate showed good flameproofing properties.- I

Attempts to obtain the results of the invention by use of each of the components individually have not been successful. If the halogenated fatty acid ester is first deposited on the cellulosic material, the adhesive does not form a bond between the materials being bonded because of the oily nature of the surface on which the oil is deposited. Reversal of these steps also is not feasible since the brominated material cannot be spread continuously over either the wet or dried adhesive.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be applied as are indicated in the claims which follow.

I claim:

1. A fiameproof adhesive composition comprising: a mixture of at least about based upon the weight of said mixture of a water-insoluble salt of a metal selected from the group consisting of arsenic, antimony, bismuth and tin, at least about 15%, by weight, of a brominated vegetable oil having at least bromine, and at least about 10%, by weight, of a polyvinyl acetate adhesive.

2. A method for treating a web of fibrous material to coat said material with an adhesive and render said material resistant to combustion, comprising: depositing on said web a composition comprising a homogeneous mixture of at least about 10%, by weight, of a brominated fatty material containing at least 20% bromine, a major amount of an adhesive which is immiscible with said brominated material, and at least about 10%, by weight, of a water-insoluble salt of a metal selected from the group consisting of antimony, arsenic, bismuth and tin, and distributing said composition over the surface of said web whereby to form a thin film of said adhesive bonded to said web, and to cause said brominated fatty material to migrate into said web.

3. A method for treating webs of fibrous cellulosic materials, coating said materials with an adhesive and rendering said materials resistant to combustion, comprising: depositing on said webs a composition comprising a homogeneous mixture of about 1080%, by weight, of a cellulose adhesive immiscible with halogenated higher fatty acid esters, about 10-80%, by weight, of a halogenated higher fatty acid ester, and about 10S0%, by weight, of a water-insoluble salt of a metal selected from the group consisting arsenic, antimony, bismuth and tin, whereby to form a thin film of said adhesive bonded to said web, and to cause said halogenated fatty acid esters to migrate into said web.

4. A flameproof paper laminate comprising: a web of paper attached to a backing material with an adhesive, said paper being impregnated with a homogeneous mixture of about 10-80%, by weight, of a cellulose adhesive immiscible with halogenated higher fatty acid esters, about 10-80%, by weight, of halogenated higher fatty acid ester, and about 10-80%, by weight, of a waterinsoluble salt. of a metal selected from the group consisting of arsenic, antimony, bismuth and tin, whereby to cause said halogenated fatty acid esters to migrate into said paper, and to form an adhesive bond with said backing material.

5. The laminate of claim 4 wherein the halogenated higher fatty acid ester is a brominated glyceride.

References Cited by the Examiner UNITED STATES PATENTS 962,877 6/1910 Aylsworth l06l5 XR 2,299,612 10/1942 Clayton et al. 106l8 2,420,644 5/1947 Athy et a1. 10615 XR 2,436,216 2/1948 Leatherman 106-48 2,881,097 4/1959 Giordano et al. -s- 10615 XR 2,924,532 2/1960 Dereich 106-15 XR 5 ALEXANDER H. BRODMERKEL, Primary Examiner.

MORRIS LIEBMAN, Examiner.

J. B. EVANS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,305 ,431 February 21 1967 George J. Peterson error appears in the above numbered pat- It is hereby certified that t the said Letters Patent should read as ent requiring correction and tha corrected below.

column 2,

Column 1 line 51 for "vary" read very line 32, for "previousely" read previously column 3, line 27, for "alumium" read aluminum column 5, line 20, after "acetate" insert emulsion Signed and sealed this 25th day of June 1968 (SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr. Attesting Officer Commissioner of Patents 

4. A FLAMEPROOF PAPER LAMINATE COMPRISING: A WEB OF PAPER ATTACHED TO A BACKING MATERIAL WITH AN ADHESIVE, SAID PAPER BEING IMPREGNATED WITH A HOMOGENEOUS MIXTURE OF ABOUT 10-80%, BY WEIGHT, OF A CELLULOSE ADHESIVE IMMISCIBLE WITH HALOGENATED HIGHER FATTY ACID ESTERS, ABOUT 10-80%, BY WEIGHT, OF HALOGENATED HIGHER FATTY ACID ESTER, AND ABOUT 10-80%, BY WEIGHT, OF A WATERINSOLUBLE SALT OF A METAL SELECTED FROM THE GROUP CONSISTING OF ARSENIC, ANTIMONY, BUSMUTH AND TIN, WHEREBY TO CAUSE SAID HALOGENATED FATTY ACID ESTERS TO MIGRATE INTO SAID PAPER, AND TO FORM AN ADHESIVE BOND WITH SAID BACKING MATERIAL. 